Electric gauge



Oct. 28, 1969 s. NEWELL 3,474,540

ELECTRIC GAUGE Filed Sept. 29, 1967 3 Sheets-Sheet 1 STROHM NEWELLINVENTOR Tam JM S. NEWELL ELECTRIC GAUGE Oct. 28, 1969 C5 Sheets-SheetFiled Sepz. 29, 1967 STROHM NEWELL INVENTOR ZWJM Oct. 28, 1969 FiledSept. 29, 196',

3 Sheets-Sheet H Mm J E M 9 I M H F 0 f R r m S w T 6 i i r a l l l 1 lI c 1 i l I P i FIG /0 United States Patent O 3,474,540 ELECTRIC GAUGEStrohm Newell, 1568 India St., San Diego, Calif. 92101 Filed Sept. 29,1967, Ser. No. 671,835 Int. Cl. G01b 7/02 US. Cl. 33-174 4 ClaimsABSTRACT OF THE DISCLOSURE My device is a gauge wherein an electriccircuit is broken by objects of a minimum size. Conversely, objectshaving a portion too small for use will not break the circuit. Lightsignals in the circuit indicate the acceptability of the objects.

BACKGROUND OF THE INVENTION My invention may be used on various objects.Use for compressor blades is very practical although its use is notlimited thereto.

As is well known in the art, compressor blades, such as those used onturbines and jet engines, frequently require reconditioning. While inuse blades are often struck by foreign particles. Also, erosion takesits toll. Reworking defective blades restores usability to some. Becausesuch reconditioning reduces the width of a portion of the blade, it isdesirable to simply and easily determine if the blade is then withinacceptable tolerances.

Existing methods of checking the reworked blades include the use ofmicrometers or indicators. Such manual operations do not involve a checkof the complete profile of the blade. If only the portions checked haveacceptable dimensions, blades with reworked but unchecked undersizeportions may erroneously be accepted as good. Also, a relatively largeamount of time is taken in transferring the reworked blade from checkpoint to check point. There is exposure to mistakes in judgment onacceptability of blades with loss of material, time and safety.

SUMMARY My invention avoids the shortcomings of the existing art. Evenby unskilled persons, the complete profiles of objects may now bechecked simply, accurately and quickly. Two parallel rows of metallic,movable fingers are an important feature of my invention. The rows areat a specified distance apart. The space between the rows is slightlyless than the minimum width of the objects to be checked.

Dual electrical circuits are formed to include the following: twoparallel insulated bar conductors which movable portions of the fingersuniformly abut; two conducting members each of which is in fixed contactwith the respective rows of fingers; an electrical energy sourceconnected thereto; dual light signals wired in series in each circuitand appropriate oif-on switches.

When an object to be checked is placed between the rows of fingers anyportion thereof that might be too narrow for use will fail to force oneor more fingers away from the bar. At least one finger contacting thebar results in an unbroken electric circuit, indicated by the lightedsignal. The operator thusly has sufiicient information to reject theinadequate object.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings showing preferredembodiments of my invention wherein like numerals indicate like partsthroughout,

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FIGURE 1 is a perspective view of my complete device with a few fingersremoved from the middle of one row thereof.

FIGURE 2 is a perspective view of one finger.

FICURE 3 is a cross-sectional view of a portion of one end of thedevice.

FIGURE 4 is a cross-sectional detail showing the position of the fingerswhen not in use.

FIGURE 5 is a cross-sectional detail showing the position the fingersmay take when an object is being checked.

FIGURE 6 is a detail of the object holder aligned with object to beinserted.

FIGURE 7 is a detail thereof in position for testing an object.

FIGURE 8 is a top view of the holding block without presence of anobject to be checked.

FIGURE 9 is same as that of FIGURE 8 with the presence of an object thatchecks good.

FIGURE 10 is like that of FIGURE 9 except an object that checks bad ispresent.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings forming apart hereof, the numeral 1 of FIGURE 1 indicates a mounting plate withsupport block 9 integral therewith. Block 9 may be formed of anysuitable non-conductive material. It preferably has the same surfacecontour as an object to be checked. That illustrated is of a compressorblade. The block functions as a master guide for aligning articles to bechecked.

Articles to be tested thereon are held in retainer 7. For compressorblades 27 slot 28 accepts the shoulders 29 thereof to stop 32. When ablade is slideably mounted in direction of the arrow of FIGURE 6, it isheld in place by screw 30.

Extended portion 31 of retainer 7 is pivotably mounted with a pin inprojections 33 of FIGURE 7. Objects may then be swung out of contactwith block 9 when being replaced.

Changes may result in the longitudinal center line of objects, such asblades, if one side is reworked more than another. Within centeringportion 8, mounted on plate 1, I have provided a common rack and gear(not illustrated). By turning of knob 38 (FIGURE 9) the operator maymove the object in direction of arrows. Desired centering of the object27 on block 9 may quickly and easily result. Duplicate adjustable stopsmay define the extent of movement as spaces 36 and 37 are occupied.

Seemed to block 9 is electrical conducting bar 12. Bar 12 is insulatedfrom block 9 which is a non-conductor. Recessed pins 10 may hold the baronto the block. This bar has the length and shape of the edge of theobject to be checked. For blades a duplicate bar 17 is also mounted onthe block parallel to bar 12.

Each bar is connected to ordinary signals such as lights 2 and 3 mountedon plate 1. Wires 18 and their counterparts 19 may carry electricalcurrent through orifice 22 of the plate from bars 12 and 17 to therespective signals. A conventional electrical power source (notillustrated) well known to skilled technicians may energize the system.One or more conventional off-on switches 4 and 5 may be hooked into thecircuit in series. Various arrangements may be made. I prefer one switch4 for connecting the bars and lights with another switch 5 connected tothe system for by-passing the hereinafter described circuit components.Testing the lights and system can result with switch 5.

A further important component of the circuitry are a plurality of novelfingers 11, best seen in FIGURE 2.

They serve as electrical conductors and are made of metal of springtemper. A relatively narrow, thin, shaft provides the needed elasticity.A straight edge base of the flattened head is formed at right angles toshaft 15. This facilitates critical operative mounting on flat surface13 of block 9, see FIGURE 1. These fingers are the link between theprofile of the object checked and the signal. They include theirregularities of certain machined parts to detection in the eye of theoperator. As such they are arranged, preferably about sixteen per inch,along the path to be occupied by the edge of the object tested. Theircloseness to each other determines the number of check points. I preferthe fingers suiiiciently close to touch one another on both sides. Inthe case of blades, as illustrated, the fingers are in two parallelstraight rows 6, see FIG- URE 8. While under slight tension all fingerstouch a described conducting bar at points 25 and 26. There issufficient force to permit a flow of current under low voltage. Thetension is weak enough, however to permit objects to force the fingersaway from the bar with slight friction. This action is shown in FIGURE5, exaggerated for purposes of illustration. In actual use the bladewould be centered.

Finally one or more finger retaining bars 14 is provided to hold the endof the shaft of all fingers permanently against the block 9. Also, beingmade of conducting metal, it completes the electric circuit for it iswired in series, to the aforementioned components. For blade checking Iuse two parallel bars 14 to hold the two rows of fingers. FIGURE 3 showsthe connections of wires and 21 with usual threaded nuts 23 on threadedstuds of the bars.

In operation an acceptable blade, having broader width than the spacebetween the bars 12 and 17, pushes all the fingers out of contact withthe bars, thusly breaking the circuit, as evidenced by a light signalgoing off. It is shown in FIGURE 9. On the other hand, a defectiveblade, with unacceptable recesses 39 permits undisturbed contact betweenblade and bar in the area of the recess. At least one finger therebymaintains the circuit, illuminating the signal.

It is to be understood that those skilled in the art may make routinemodifications hereof which will fall within the scope of my describedinvention.

I claim:

1. In an electric gauge the combination of:

(a) a mounting block,

(b) a supporting block integral therewith,

(c) a plurality of movable fingers aligned in two oppositely disposedstraight parallel rows along each side of the block,

(d) dual conducting bars positioned on the support block, each of whichis electrically engagea'ble by all the fingers in the row nearestthereto,

(e) dual retaining bars each of which is always in electrical contactwith all the fingers of one of the rows,

(f) electrically activated signal means connected in series withthereamining bar and conducting bar,

(g) means for rtaining a blade to be gauged between the rows of fingers,

(h) means for laterally adjusting the position of the blade in respectto the rows of fingers.

2. The claim according to claim 1 wherein the signal means is a lightbulb.

3. The claim according to claim 1 wherein the means for retaining ablade is provided with adjustable screw means for securing the bladeWithin a swivelly mounted holder.

4. The claim according to claim 1 wherein the means for laterallyadjusting the position of the blade consists of a manually rotatableknob operatively connected to the means for retaining a blade.

References Cited UNITED STATES PATENTS 1,682,464 8/1928 Arelt et al.

1,766,991 6/1930 Gardner 33l74 X 2,977,533 3/1961 Savage 33174 X3,080,659 3/1963 Wolford 33-174 SAMUEL S. MATTHEWS, Primary Examiner

